JP2022509605A - Systems and methods for finding adjacent nodes in a network - Google Patents

Abstract

The disclosure includes the discovery of neighboring nodes in the network. For example, a method of discovering a neighbor node includes receiving a neighbor solicitation message at the first node. The neighbor solicitation message includes an indication that the second node is a low power device and a first scheduled response time. The method also comprises sending a first neighborhood advertising message by the first node at a scheduled response time. The first neighborhood advertising message includes an indication that the neighborhood cache of the first node is not available and a second scheduled response time. Further, the method is to remove one or more nodes from the neighbor cache and a second node from the second node that indicates availability in the neighbor cache at the first node at the second scheduled response time. Includes receiving 2 neighborhood solicitation messages. Further, the method comprises linking the first node and the second node.

Description

The present disclosure relates, in general, to the process for finding adjacent nodes in a network. More specifically, the present disclosure limits the consumption of bandwidth used in such discovery processes, while soliciting neighbors and neighbors to discover potential neighbor nodes that could be potential parent-child node links. Regarding the use of advertisements.

Network systems such as Internet of Things (IoT) devices, such as smart power, gas, water meters and other smart electronic devices, can be interconnected for device-to-device communication and with the Internet or other networks. It is possible to connect to each other. For example, IoT systems provide the ability for IoT devices to communicatively bind to each other and exchange data. An IoT system may include a set of parent nodes that connect to a network (eg, the Internet or an intranet), either directly or indirectly through an additional layer of parent nodes. The IoT system may also include a set of child nodes that link with a parent node or other child nodes and exchange data above and below the node chain that forms the IoT system.

The discovery of adjacent nodes in IoT systems raises certain issues. For example, a large number of messages may be exchanged during adjacency discovery of the entire IoT system, which can overwhelm the communication bandwidth of the IoT system. In addition, low power devices may wake up frequently to catch up with adjacency discovery messages, prematurely draining power from low power devices. In addition, the irreversible nature of the communication of the entire IoT system can result in excessive re-transmission of messages, which promotes over-consumption of the communication bandwidth of the IoT system. Thus, over-consumption of communication bandwidth in adjacency discovery can reduce or block the available bandwidth for data transmission, increase latency in the network, or power low power devices. It may limit the life.

Aspects and examples of devices and processes for discovering neighboring nodes are disclosed. For example, a method of discovering a neighbor node includes receiving a first neighbor solicitation message at the first node. The first neighbor solicitation message includes a first indication that the second node is a low power device and a first scheduled response time. The method also comprises sending a first neighborhood advertising message on the first node at the first scheduled response time. This neighborhood advertising message includes a second indication that the neighborhood cache of the first node is not available and a second scheduled response time. Further, the method involves removing one or more nodes from the neighboring cache. Further, the method comprises receiving a second neighbor solicitation message from the second node by the first node at the second scheduled response time and linking the first node with the second node. ..

In another example, a node in the network includes a processor that executes computer-readable instructions. The node also contains memory that stores computer-readable instructions that, when executed by the processor, cause the processor to perform operations. Operations performed by the processor include receiving a first neighbor solicitation message from an additional node, including a first scheduled response time. Further, the operation includes sending a first neighborhood advertising message to an additional node and establishing a link with the additional node at the first scheduled response time.

In a further example, the node includes a processor that executes computer-readable instructions and a memory that stores computer-readable instructions that cause the processor to perform operations when executed by the processor. Operations performed by the processor include establishing a link with a potential parent node. In addition, the operation involves receiving a non-solicitation neighbor advertising message from a potential parent node indicating a potential parent node status change. In addition, the operation involves updating the neighbor cache stored in memory to accommodate potential parent node status changes.

These exemplary embodiments and features are referred to not to limit or define the invention of the present invention described herein, but to provide examples that aid in understanding the concepts described herein. Other aspects, advantages, and features of the invention currently described will become apparent after reviewing the entire application.

These and other features, embodiments, and advantages of the present disclosure will be better understood by reading the detailed description of the invention below with reference to the accompanying drawings.
FIG. 1 is a block diagram showing an example of an Internet of Things (IoT) system according to one or more embodiments. FIG. 2 is an example of a process for finding an adjacent node in an IoT system according to one or more embodiments. FIG. 3 is an example of a target address option format of a neighborhood advertising message according to one or more embodiments. FIG. 4 is an example of a node status option format of a neighborhood advertisement message or a neighborhood solicitation message according to one or more embodiments. FIG. 5 is an example of a device capability option format for a neighborhood advertising message or neighborhood solicitation message according to one or more embodiments. FIG. 6 is an example of a scheduled time option format for a neighborhood advertising message or neighborhood solicitation message for one or more embodiments. FIG. 7 is an example of a process for communicating IP address changes between linked nodes according to one or more embodiments. FIG. 8 is an example of a process for establishing a link between nodes when the parent node's neighborhood cache is full, according to one or more embodiments. FIG. 9 is an example of a process for removing links between nodes when the parent node's neighborhood cache is full, according to one or more embodiments.

Systems and methods for discovering neighboring nodes in the network are provided. For example, within an Internet of Things (IoT) system, a node can send and receive data to and from other nodes or centralized networks (eg, the Internet or Intranet) at any point within the IoT system. be. To provide proper routing between a node and a centralized network, the IoT system relies on a unique identifier (eg, a unique IP address) associated with each node to send data between the nodes. Provides an Internet Protocol (IP) based infrastructure.

In order for the new node to join the IoT system, each of the new nodes can identify neighboring nodes that have the available capacity to receive data from the new node and provide data to the new node. Identifying a neighbor node that may be a potential parent node is referred to herein as a neighborhood discovery operation. The techniques described in the present disclosure can provide a mechanism for reducing communication bandwidth consumption due to neighborhood discovery operations and efficiently generating reliable communication links between nodes within an IoT system. Therefore, the particular implementation described herein provides the IoT system with a particular process that provides a reduction in data bandwidth consumption in neighborhood discovery operations.

FIG. 1 is a block diagram showing an example of an Internet of Things (IoT) system 100. The IoT system 100 allows smart devices (eg, resource consumption meters, vehicles, home appliances, etc., including communication technologies) to communicate over a network of nodes (ie, smart devices), the Internet, and / or an intranet. Provides the network infrastructure of. In an example where the IoT system 100 creates a mesh network of smart utility meters, the IoT system 100 includes a headend 102 that can function as a central processing system that receives a stream of data from the network 104. The network 104 may be the Internet, an intranet, or any other data communication network. The root node 106 and the child nodes 108, 109 collect data related to the nodes 106, 108, 109, and the root node 106 transmits the collected data to the network 104 and finally to the headend 102. The root node 106 may be a personal area network (PAN) coordinator, an internet gateway, or any other device that can connect to the network 104.

The root nodes 106a and 106b may generally be referred to as parent nodes by a data link with a child node 108 located in the node layer below the root nodes 106a and 106b (eg, layer 1). For example, the root nodes 106a and 106b are shown to communicate directly with the network 104. Due to the direct communication between the root nodes 106a and 106b and the network 104, the data provided by the child nodes 108 will pass through fewer nodes to reach the network 104 and the headend 102.

Since the child node 108 is located at layer 1 of the network of the IoT system 100 and the child node 109 is located at layer 2 of the IoT system 100, the child node 108 linked to the child node 109 is called a parent node. There is also. For example, the data from the child node 109 may travel through the child node 108 and the root node 106 before the data reaches the network 104 and the headend 102, while the data from the child node 108 , Travel via only the root node 106 before reaching the network 104 and the headend 102. Only the root layer (ie, root node 106), layer 1 (ie, child node 108), and layer 2 (ie, child node 109) are shown in FIG. 1, but more or less. , Layers may be included in the IoT system 100. Further, although FIG. 1 depicts a particular network topology (eg, DODAG tree), other network topologies are possible (eg, ring topology, mesh topology, star topology, etc.).

As mentioned above, other nodes further away from the network 104 than the root nodes 106a, 106b can also be suitable parent nodes. For example, a node that has a mains as the power source for the node can be a more reliable parent node than a battery-powered node (eg, a low power device). Therefore, the child node 108 or 109 is between a battery power node that is in direct communication with the network 104 and a main power node that is at least a node layer away from direct communication with the network 104 or direct communication with the root node 106. When the task is to select the parent node, the child node 108 or 109 may select the main power node as the parent node. This choice may be based on the main power node providing a constant communication path to the child nodes while the battery power node may enter sleep mode on a regular basis to save battery power.

In one example, a low power device 110 that is not currently linked to a neighboring node, or any other node 108 or 109, is a neighboring or potential parent suitable for the communication strategy of the low power device 110 or other node 108 or 109. You can perform a neighborhood discovery operation to identify a node. The neighborhood discovery operation is described below with respect to the low power device 110, but any node 108 or 109 may perform the neighborhood discovery operation in a similar manner. In the neighborhood discovery operation, the low power device 110 sends a neighborhood solicitation message to any of the nodes 106a, 106b, 108, and 109 within the communication range of the low power device 110. In one example, the low power device 110 uses a radio frequency (RF) transmitter, RF transceiver, or any other communication device to transmit a neighborhood solicitation message.

The nodes 106a, 106b, 108, and 109 that receive the solicitation message are the availability status for linking with the new neighbor node and which node is the best candidate available to establish the link. Neighboring advertising messages exhibiting other characteristics of nodes 106a, 106b, 108, or 109 that can assist the low power device 110 in determining can be returned to the low power device 110. For example, the nodes 106a, 106b, 108, 109 may transmit an indication of whether the nodes 106a, 106b, 108, 109 are mains or battery powered. In addition, nodes 106a, 106b, 108, 109 may transmit other indications, including node capability, target address information, node status information, and time scheduling information.

Based on the information received from nodes 106a, 106b, 108, and 109 in the neighborhood advertisement message, the low power device 110 selects between nodes 106a, 106b, 108, and 109 for the bidirectional node data link. May be good. As an example, the root node 106b may provide a display in a neighborhood advertising message that the root node 106b is one node layer away from the network 104, and the neighborhood advertising message is such that the root node 106b is the root node 106b. It may be shown that it has one child node 108 that is already linked. Comparing the neighborhood advertisement message from the root node 106b with the neighborhood advertisement message from the root node 106a and the child nodes 108, 109, the proximity of the root node 106b to the network 104 and the root node 106b being less than the root node 106a. Any indication that the child node 108 is linked can affect the creation of a bidirectional data link between the root node 106b and the low power device 110. Other considerations may also affect the selection of the parent node by the low power device 110.

FIG. 2 is an example of the process 200 for discovering neighboring nodes in the IoT system 100. At block 202, process 200 includes node 106, 108, or 109 receiving a neighbor solicitation message from a neighbor device. Neighbor solicitation messages may include a request for a scheduled response time. In one or more examples, the neighbor device may be the low power device 110 depicted in FIG. 1, such as a utility meter with battery power. In such an example, the low power device 110 may frequently enter and exit sleep mode to save energy. Thus, the scheduled response time provides node 106, 108, or 109 with an indication of when the low power device 110 will be available to receive a response to the neighbor solicitation message of the low power device 110. It may be a thing.

At block 204, process 200 includes determining the priority level of the neighbor device based on the neighbor solicitation message. As an example, a neighbor solicitation message received by node 106, 108, or 109 may provide an indication of the device capabilities of a neighboring device. The device capacity may include power capacity, resource capacity, prioritization requirements, device throughput capacity, and the like. In such an example, node 106, 108, or 109 may use device capability information to determine how node 106, 108, or 109 responds to a neighbor solicitation message. Further, in an example where a plurality of node solicitation messages are received by node 106, 108, or 109, node 106, 108, or 109 may prioritize neighboring devices that send node solicitation messages. For example, node 106, 108, or 109 may prioritize the low power device 110 above the mains node that sent the node solicitation message to node 106, 108, or 109 within the same time window as the low power device 110. May be promoted to the priority level of. Thus, a node 106, 108, or 109 may send different node advertising messages to the low power device 110 and the mains node based on different priority levels and to the low power device before responding to the mains node. Can respond.

At block 206, process 200 includes sending a neighbor advertising message to a neighbor device. Node 106, 108, or 109 may send a Neighbor Advertisement message to a Neighbor Device during the scheduled response time indicated in the Neighbor Solicitation Message. In one example, the neighborhood advertising message may include node status indicating various states, conditions, or errors with respect to node 106, 108, or 109. Neighboring devices may use the node status information to determine whether the neighboring device establishes a link with node 106, 108, or 109 or seeks an alternative node to join.

Neighboring advertising messages may also include the target address of node 106, 108, or 109. The target address informs neighboring devices of a plurality of IPv6 addresses that the node 106, 108, or 109 may have for each link layer address. In addition, neighborhood advertising messages may include device capabilities such as power capacity, resource capacity, priority, and so on. In an example where node 106, 108, or 109 is a low power device (eg, a battery-powered meter), the Neighbor Advertisement message is that the Neighbor Device receives the next scheduled Neighbor Advertisement message or other scheduled data message. It may also include a scheduled time to do so. Other information about neighborhood advertising messages is also intended to be within the scope of this disclosure.

When communicating between nodes 106, 108, 109, 110 to identify neighbor devices that may be suitable for bidirectional data links, neighborhood advertising and solicitation messages to help establish the data link. Various information can be provided at. Further, the neighborhood advertising message may be solicited (eg, in response to a neighborhood solicitation message from another node), and the neighborhood advertising message may be non-solicited (eg, neighbor solicitation message or). It may be one that does not respond to the neighborhood advertisement message). As an example, FIGS. 3-6 include data format options available for communication between nodes 106, 108, 109, 110. The information provided in the data format options of FIGS. 3-6 may help node 106, 108, 109, or 110 identify a suitable parent node for reliable bidirectional communication.

FIG. 3 is an example of the format of the target address option 300 in a neighborhood advertising message. The target address option 300 provides information about a plurality of IPv6 addresses included for each link layer address of the node in the neighborhood advertisement message. The target address option 300 may include a type display 302 that provides an 8-bit identifier for the option type to be followed. For target address option 300, the type display 302 indicates that the option type is a target address option.

After establishing the option type, the target address option 300 includes a length identifier 304. The length identifier 304 may include an 8-bit unsigned integer containing information about the data length of the target address option 300 including the type indicator 302 and the length identifier 304. The value of the length identifier 304 may be provided in octet units and a value of 0 is invalid. For example, a display of at least two octets may be provided by the length identifier 304 to indicate the presence of the type display 302 and the length identifier 304.

The display of the number of link layer addresses 306 may also form part of the target address option 300. The link layer address number display 306 may include an 8-bit unsigned number containing information about the number of link layer addresses available within the node 106, 108, or 109 that sends the Neighbor Advertising message. A typical node 106, 108, or 109 may generally provide an indication that the number of available link layer addresses is one. However, other numbers of available link layer addresses are also contemplated.

One or more reserved fields 308 may be included at the end of several rows of data. One or more reserved fields 308 are variable in length and provide padding to the line of data so that the final structure of the target address option 300 is a 32-bit alignment. That is, the target address option 300 contains 32-bit data in each row of data for the entire target address option 300.

The first target media access control (MAC) address 310 may be included as part of the target address option 300. The first target MAC address 310 is an 8-byte value of the first target MAC address of the node 106, 108, or 109 that sends a neighborhood advertisement message. Since the size of the first target MAC address 310 is 64 bits (ie, 8 bytes), the first target MAC address 310 is provided over two 32-bit lines of data in target address option 300. May be good.

A display 312 of the number of IPv6 interfaces may be included in the target address option 300 to indicate how many IPv6 interfaces are present in the first target MAC address 310. The display 312 is an 8-bit unsigned number. This 8-bit unsigned number includes the number of IPv6 interfaces available at the first target MAC address 310. Each of the IPv6 interfaces available at the first target MAC address 310 can be identified by the target IPv6 address 314. Each target IPv6 address 314 may contain 16 bytes. Therefore, the data size of the target IPv6 address 314 can be scaled based on the display 312 of the number of target IPv6 interfaces available at the first target MAC address 310.

After the target IPv6 address 314 is provided with the target address option 300, the variable field 316 may provide additional information about the additional target MAC address. For example, if the number of link layer addresses 306 indicates that the node 106, 108, or 109 contains more than one link layer address, the variable field 316 may output information related to the additional target MAC address. Further, the variable field 316 may indicate a target IPv6 address associated with an additional target MAC address in a format similar to the first target MAC address 310. For example, the variable field 316 may include a field indicating the number of IPv6 interfaces and the target IPv6 address associated with that IPv6 interface.

The display of the number of link layer addresses 306, the target MAC address 310, the display of the number of IPv6 interfaces 312, and the target IPv6 address 314 included in the solicitation or non-solicitation neighborhood advertisement message are information from one node to another. Enables efficient transmission. In addition, the target address option 300 contained in a single Neighbor Advertising message reduces communication bandwidth disruption when updating Neighbor Cache entries. Further, the target address option 300 in the neighboring advertisement message increases the possibility that the receiving node receives all the information related to the target address option 300 by including all the information in each advertisement message.

FIG. 4 is an example of one of the formats of node status option 400 for a neighborhood advertisement message or a neighborhood solicitation message. When identifying potential data links across nodes 106, 108, 109, 110, it may be useful for nodes 106, 108, 109, 110 to provide a status display for the node. Thus, neighborhood advertising messages and / or neighborhood solicitation messages may include node status option 400.

The node status option 400 may include a type display 402 that provides an 8-bit identifier for subsequent option types. For node status option 400, the type display 402 indicates that the option type is a node status option. The node status option 400 also includes a length identifier 404. The length identifier 404 may include an 8-bit unsigned integer containing information about the data length of the node status option 400 including the type indicator 402 and the length identifier 404. The value of length identifier 404 can be provided in octet units, a value of 0 is invalid. For example, in addition to any octet associated with the node status indicator 406, the display of at least two octets indicating the presence of the type indicator 402 (first octet) and the length identifier 404 (second octet) is of length. It can be indicated by identifier 404.

The node status indicator 406 may include a 16-bit unsigned number indicating the status of nodes 106, 108, 109, and / or 110. In one example, the node status indicator 406 may provide a data code representing the node status. In such an example, a value of 0 can indicate success status, a value of 1 can indicate no IP layer connectivity, a value of 2 can indicate that the neighbor cache is full, and a value of 3. Can indicate that a neighboring cache entry has been deleted, and a value of 4 can indicate a provisional cache entry. Other statuses and codes related to the status of nodes 106, 108, 109, and 110 are also intended to be within the scope of this disclosure.

In one or more examples, the node status indicator helps determine if the low power device 110 should seek a different potential parent node after receiving a Neighbor Advertising message containing the node status option 400. obtain. For example, if the node status indicator 406 indicates that the potential parent node's neighborhood cache is full, the low power device 110 is a one-way flow of information (eg, data from the low power device 110 to the root node 106). A different parent node may be sought to avoid the flow (not the data flow from the root node 106 to the low power device 110). In addition, the node status indicator 406, which indicates adjacent cache entry deletion or provisional cache entry, may prompt the low power device 110, or other node 108 or 109, to pursue other potential parent node options. Further, the node status indicator 406 may provide an indication of the number of neighboring links at node 106, 108, or 109. In addition, the node status indicator 406 may provide an indication of the maximum number of neighbor links available at node 106, 108, or 109.

As an example, a node status indicator 406 indicating an interim cache entry allows the low power device 110, or another child node 108 or 109, to establish an interim link with the root node 106, or any other node 108 or 109. The indication that it can be provided may be provided to the low power device 110, or another child node 108 or 109. The tentative cache entry is a tentative cache location reserved inside the neighbor cache on the root node 106 or on another node such as node 108 or 109, depending on which node caches the entry. There may be. The provisional cache location is the child node 108 or 109 or low while the child node 108 or 109 or the low power device 110 finds a parent node with more available space in the non-provisional portion of the adjacent cache. The ability to tentatively link with the power device 110 may be provided to the root node 106. Therefore, the interim cache location can act as a cache location reserved for the low power device 110. For example, the root node 106 may have a provisional cache location available for provisional linking with the low power device 110 when requested. The tentative link between the low power device 110 or other child node 108 or 109 and the root node 106 in such an example is not permanent and the root node 106 is the low power device 110 or other. The tentative link between the child node 108 or 109 and the root node 106 may eventually be removed. By indicating the nature of the interim link with the node status indicator 406, the low power device 110 or other child nodes 108 or 109 may identify different potential parent nodes in pursuit of a more persistent link. ..

Further, if a link has already been established between the low power device 110 and the root node 106 or another node 108 or 109, the low power device 110 may have a different adjacent node or a potential parent node. By establishing a new link, node status indicators with no IP layer connectivity can be addressed. When establishing a new link, the low power device 110 removes information about the original root node 106 from the low power device 110's neighborhood cache and the low power device 110's neighborhood cache with respect to the new neighbor or potential parent node. Information can be updated.

The process of finding a new parent node for the low power device 110 may track the process 200 described above with respect to FIG. For example, the low power device 110 may send a node solicitation message to a group of other potential parent nodes when it finds that communication with the root node 106 is impaired for some reason. Other potential parent nodes may provide post-solicitation neighborhood advertising messages detailing the capabilities and status of the potential parent node. The low power device 110 has the potential to determine that the low power device 110 provides optimal communication capability for the low power device 110 (eg, number of layers from the mains node, root node 106, availability of neighborhood cache, etc.). It may be linked with one of the parent nodes.

FIG. 5 is an example of the format of device capability option 500 for a neighborhood advertising message or a neighborhood solicitation message. Providing the device capabilities of nodes 106, 108, 109, 110 in identifying potential data links across nodes 106, 108, 109, 110 can be beneficial to nodes 106, 108, 109, 110. .. Thus, neighborhood advertising messages and / or neighborhood solicitation messages may include device capability option 500.

Device capability option 500 may include a type display 502 that provides an 8-bit identifier for the option type to be followed. For device capability option 500, the type display 502 indicates that the option type is a device capability option. The device capability option 500 also includes a length identifier 504. The length identifier 504 may include an 8-bit unsigned integer containing information about the data length of the device capability option 500 including the type indicator 502 and the length identifier 504. The value of the length identifier 504 may be provided in octet units and a value of 0 is invalid. For example, in addition to any octet associated with the device capability indicator 506, the display of at least two octets indicating the presence of the type indicator 502 (first octet) and the length identifier 504 (second octet) is length. It can be indicated by identifier 504.

The device capability indicator 506 may include a 16-bit unsigned number indicating the device capability of the nodes 106, 108, 109, and / or 110 to send a message containing the device capability. In one example, the device capability indicator 506 may store a data code that is representative of the device capability. In such an example, a value of 0 may indicate a mains device, a value of 1 may indicate a battery-powered device, a value of 2 may indicate a router device, and a value of 3 the device prioritizes traffic. A value of 4 may indicate that the device requires binding prioritization, a value of 5 may indicate a low throughput device, and a value of 6 may indicate a low traffic device. Any other device capability of the nodes 106, 108, 109, and 110 that would be desirable to present to another node of the nodes 106, 108, 109, and 110 is also within the scope of the present disclosure. Is planned.

In one or more examples, the device capability indicator 506 is how the low power device 110, the root node 106, and / or the child nodes 108, 109 send a neighbor advertisement message including the device capability option 500. Can help determine if it interacts with. For example, if the device capability indicator 506, typically in a node solicitation message, indicates that the device is a low power device 110 and wants a parent node, then the root node 106 that receives the device capability indicator 506. May reorganize the links with other nodes in order to prioritize establishing the links with the low power device 110. Similarly, the device capability indicator 506 from the potential parent node provides sufficient device capability for the low power device 110 or other child node 108 or 109 for the potential parent node to establish a bidirectional data link. It may be possible to determine if it is being provided. In addition, the device capability indicator 506 provides information about the node's ability to issue neighborhood advertisements and solicitation messages while maintaining independence from other layers of the network stack.

FIG. 6 is an example of one of the formats of the scheduled time option 600 for a neighborhood advertising message or a neighborhood solicitation message. If one or more of the nodes 106, 108, 109, and 110 are low power devices (eg, the nodes 106, 108, 109, and 110 include battery power), the node sleeps for a significant amount of time. It may be in a state. When nodes 106, 108, 109, and 110 are in sleep mode, nodes 106, 108, 109, and 110 may not be able to receive messages from other nodes or devices. Thus, the neighborhood advertising message and / or the neighborhood solicitation message provides a scheduled time option 600 indicating a time schedule that the node 106, 108, 109, or 110 sending the message will have available to receive the response. , May be included.

The scheduled time option 600 may be included in multiple scenarios. For example, the scheduled time option 600 may be commonly used in a neighborhood solicitation message to indicate a time schedule in which nodes 108, 109, or 110 are ready to receive a response. In another example, the scheduled time option 600 may be included as a single component of the Neighbor Advertising message. When used as a single component of a Neighbor Advertising Message, the Scheduled Time Option 600 indicates the time when a subsequent Neighbor Advertising Message is sent to Solicitation Node 108, 109, or 110. In addition, the Neighbor Advertisement message provides a node status option 400 with a scheduled time option 600 to trigger an indication of the time at which the solicitation node 108, 109, or 110 can attempt to send a subsequent neighbor solicitation message. Can include. Further, when node 108, 109, or 110 solicits neighbor node information via a node solicitation message that includes a scheduled time option 600, the neighbor node is before the scheduled time indicated in the node solicitation message. , You can create a space in the cache. Therefore, the neighbor advertisement message may respond to the cache availability indication using the node status option 400 without including the scheduled time option 600.

The scheduled time option 600 may include a type display 602 that provides an 8-bit identifier for the option type to be followed. For the scheduled time option 600, the type display 602 indicates that the option type is a scheduled time option. The scheduled time option 600 also includes a length identifier 604. The length identifier 604 may include an 8-bit unsigned integer containing information about the data length of the scheduled time option 600 including the type indicator 602 and the length identifier 604. The value of the length identifier 604 may be provided in octet units and a value of 0 is invalid. For example, the presence of a type indicator 602 (first octet) and a length identifier 604 (second octet) in addition to the control field 606, the reserved field 608, and any octet associated with the scheduled time indicator 610. A representation of at least two octets to indicate can be indicated by the length identifier 604.

The control field 606 may include an 8-bit number that specifies the time format of the scheduled time indicator 610. For example, if the value of the control field 606 is 0, it may specify that the time format of the scheduled time indicator 610 is the Greenwich Mean Time (GMT) format. Alternatively, if the value of the control field 606 is 1, it may be specified that the time format of the scheduled time indicator 610 is in milliseconds from the transmission time of the message including the scheduled time option 600.

The reserved field 608 may be included at the end of a row of data for the scheduled time option 600. As shown, the reserved field 608 is arranged between the control field 606 and the scheduled time 610. The reserved field 608 is variable in length and the reserved field 608 provides padding for rows of data such that the final structure of the scheduled time option 600 is a 32-bit alignment. Since the type display 602, the length identifier 604, and the control field 606 occupy the first 24 bits of the first row of data, the reserved field 608 is for padding the last 8 bits of the first row of data. Used for.

The scheduled time indicator 610 is located in the second row of data and contains a 32-bit unsigned number. The value provided by the scheduled time indicator 610 specifies the scheduled time at which the device sending the node solicitation message will be available to receive the response. As mentioned above, the scheduled time indicator 610 may be provided in GMT format or may be provided in milliseconds from the transmission time. Other time formats presented by the scheduled time indicator 610 are also intended to be within the scope of the present disclosure. In one or more examples, the solicited neighborhood advertising message may include a scheduled time indicator 610 in the message from the potential parent node to the node that originally sent the neighbor solicitation message. In such an example, the Neighbor Advertisement message has a node status option 400 indicating that it is currently unavailable, and a room for a new Neighbor Node Link where the potential parent node clears part of the Neighbor Cache. Can include a scheduled time option 600 with a scheduled time indicator 610 indicating the amount of time for a node soliciting a neighboring node link to wait while performing an operation to create. If the Neighbor Advertisement message includes a Scheduled Time Indicator 610 without the Node Status Option 400, the Scheduled Time Indicator 610 may indicate when subsequent Neighbor Advertisement messages will be sent.

When the neighbor solicitation message and the neighborhood advertisement message include the scheduled time option 600, the low power device 110 that asks for a parent node link, asks for a status update, or provides a neighborhood solicitation message is the low power device 110. You can save battery power by avoiding awakening times while new messages are not expected to arrive at. It may also increase the likelihood that the low power device 110 will receive the message. For example, the low power device 110 may send a neighbor solicitation message at the response time indicated by the scheduled time option 600. Therefore, the low power device 110 may sleep until the response time is satisfied. At that point, the low power device 110 may wake up and receive messages from other nodes.

Similarly, the mains node provides the low power device 110 with a scheduled time indicator 610 in anticipation that the mains node will tentatively clear the neighborhood cache space for the low power device 110. May be good. In such an example, the low power device 110 may re-enter sleep mode and awaken to retry the neighbor solicitation message at a scheduled time. While saving the battery power of the low power device 110, the scheduled time option 600 can reduce the number of messages used to receive the appropriate response on the low power device 110. Further, the scheduled time option 600 increases the overall probability of receiving a neighbor advertisement message on the low power device 110 by providing a time window for the low power device 110 to wake up and receive the message. I can let you.

Data formats 300, 400, 500, and 600 are described above as separate messages, but all or any combination of data formats 300, 400, 500, and 600 may be neighborhood advertising messages, neighborhood solicitation messages, or both. May be provided as a new or additional component of. For example, a neighbor solicitation message from the low power device 110 may include a device capability option 500 and a scheduled time option 600. Further, the neighbor advertising message from the root node 106 may include a target address option 300, a node status option 400, a device capability option 500, and a scheduled time option 600. Other combinations of formats 300, 400, 500, 600 are also contemplated for both node solicitation messages and node advertising messages.

Next, with reference to FIG. 7, one example of a process 700 for communicating IPv6 address changes between linked nodes is provided. In one example, linked nodes (eg, one of root node 106a and child node 108) may communicate with each other using neighborhood advertising messages that are either solicited or non-solicited. Neighbor advertising messages between linked nodes are status changes from one of the linked nodes to the other linked node, node capability from one of the linked nodes to the other linked node, linked. Communicate scheduled response times from one of the nodes to the other linked node, display of IPv6 address changes from one of the linked nodes to the other linked node, or any combination thereof. Can be used for. As an example, process 700 details the communication of IPv6 address changes, but similar techniques may be used for other communication between linked nodes. At block 702, process 700 includes detecting an IPv6 address change on the root node 106a or the parent node. When the IPv6 address is changed on the root node 106a or the parent node, the root node 106a or the parent node changes the child node 108 and the changed root node 106a or the parent node in order to avoid the loss of data transmission over the root node 106a. Any other node linked to the node can be updated as soon as possible.

At block 704, process 700 includes sending a non-solicitation neighbor advertising message indicating an IPv6 address change to any awake neighbor node. The root node 106a or the parent node 106a or the parent node, even if some of the nodes that link to the root node 106a or the parent node are low power devices and are likely not in an awake state when the root node 106a or the parent node detects an IPv6 address change. Upon detecting an IPv6 address change, the node may send a Neighbor Advertisement message to all adjacent nodes available to receive the message. In this way, as many neighboring nodes as possible receive the IPv6 address change indication as soon as possible. As an example, the root node 106a or the parent node may send an IPv6 address change using the target address option 300, as described above with respect to FIG.

At block 706, process 700 includes sending a scheduled Neighbor Advertising message indicating an IPv6 address change to a Neighbor Node that was sleeping during a non-solicitation Neighbor Advertising message. The scheduled time may be based on the receipt of a node solicitation message or node advertising message from a low power device that includes the scheduled time option 600, as described above with respect to FIG. Scheduled Neighbor Advertising Messages indicating IPv6 address changes are scheduled at the time indicated by Scheduled Time Option 600, and Neighbor Advertising Messages may include Target Address Option 300. In this way, process 700 can provide an IPv6 address change update to a neighboring device in an efficient manner, taking into account the neighboring device that is inactive when the IPv6 address change is discovered.

FIG. 8 is for establishing a link between the root node 106 or other potential parent node and the low power device 110 when the neighborhood cache of the root node 106 or other potential parent node is full. It is an example of the process 800. At block 802, process 800 receives a neighbor solicitation message indicating that the low power device is soliciting the establishment of a bidirectional link and reserves an entry for the low power device in the cache of the potential parent node. Including requesting. The neighbor solicitation message includes a device capability option 500 and a scheduled time option 600 from the low power device 110 to indicate that the low power device is battery powered and the low power device 110 responds to the neighbor solicitation message. Can be provided with an indication of when to anticipate. Other details regarding the low power device 110 may also be included as part of the neighborhood solicitation message.

At block 804, process 800 includes determining if the potential parent node's neighborhood cache is full. The neighbor cache of the potential parent node may be a database that stores the link between the link layer address and the IPv6 address. If the neighbor cache is full, any soliciting node (eg, low power device 110) that wants to link with a potential parent node is forced into a one-way flow of data in establishing the data link. That is, the flow of information may move from the soliciting node to the potential parent node, but the potential parent node may not be able to provide data to the soliciting node.

If the neighbor cache of the potential parent node is full, in block 806, process 800 indicates that the neighbor cache is full and indicates the scheduled time for the low power device 110 to retry, soliciting. It involves sending a later neighborhood advertising message to the low power device 110. This neighborhood advertising message may be sent to the low power device 110 at the scheduled time indicated by the low power device 110 during the node solicitation message. In such an example, the neighborhood advertising message may include a node status option 400 and a scheduled time option 600 to provide the low power device 110 with a neighborhood cache full update and the requested response time.

In another example, in block 806, process 800 comprises sending a solicited neighborhood advertising message to the low power device 110 with a scheduled time display. If the Neighbor Advertising message contains a scheduled time display without a status indicator (eg, with no indication that the Neighbor Cache is full), the potential parent node is scheduled for the potential parent node. It provides an indication that a subsequent neighbor advertisement message will be sent in time (eg, instead of receiving a subsequent neighbor solicitation message from the low power device 110). Therefore, the low power device 110 may be awakened to receive a subsequent neighbor advertisement message at the scheduled time indicated in the solicited neighbor advertisement message.

At block 808, process 800 releases the potential parent node's neighborhood cache space to create room for a bidirectional data link between the potential parent node and the low power device 110. include. The low power device 110 provided an indication of the low power nature of the low power device 110 in the node solicitation message, so that the low power device 110 has an increased priority level compared to another device on the mains. Can have. For example, the low power device 110 relies on a bidirectional data link with higher reliability than the mains device because the mains device remains awake and can transition more easily between potential parent nodes. Can be. Therefore, the potential parent node may free the cache space by removing the node from the neighboring cache, which has a lower priority than the low power device 110.

The limited power nature of the low power device 110 provides an elevated priority at the potential parent node in the example above, but other device capabilities shown in device capability option 500 also provide a neighbor solicitation message. May result in an increased priority level for the solicitation node 108 or 109 to generate. For example, the solicitation node 108 or 109 has the device capability indicator 506 that the child node 108 or 109 depends on a shorter network join time and a shorter traffic turnaround time, producing an increased level of traffic criticality. Or, if it indicates that it has other device capabilities that deserve the increased priority, it may receive the increased priority level by the potential parent node. In another example, the solicitation node 108 or 109 indicates that the solicitation node 108 or 109 has a device capability indicator 506 indicating that the solicitation node 108 or 109 has a low data throughput requirement, or if the solicitation node 108 or 109 is a low traffic generation device. In addition, it may receive a lower priority by a neighboring node or a potential parent node.

At block 810, process 800 receives a second neighbor solicitation message from the low power device 110 at the scheduled time indicated in the neighborhood advertising message provided to the low power device 110 by the potential parent node. include. The second neighbor solicitation message from the low power device 110 is because the low power device 110 provides the device capability (eg, an indication that the low power device 110 is battery powered) and the potential parent node provides a response. It may be a repeat of the first neighbor solicitation message that provides an indication of the scheduled time of.

In the example at block 806, where the neighbor advertising message from the potential parent node contains a scheduled time indicator without a status indicator, the potential parent node follows at block 810 to the low power device 110. May send neighborhood advertising messages. Subsequent neighborhood advertising messages are sent on behalf of receiving a second neighbor solicitation message from the low power device 110. In such an example, subsequent Neighbor Advertising messages may include a status indicator indicating that there is space in the Neighbor Cache of the potential parent node.

When the neighboring cache space is freed at the potential parent node, at block 812, process 800 involves establishing a bidirectional data link between the potential parent node and the low power device 110. Further, the potential parent node may respond to the neighbor solicitation message from the low power device 110 by the neighborhood advertisement message at the scheduled time. The Neighbor Advertisement message may include a target address option 300 indicating the target MAC address and IPv6 address of the potential parent node. In addition, the Neighbor Advertisement message may provide a node status option 400 with a node status indicating that the bidirectional data link is successful.

If at block 804 it is determined that the neighbor cache of the potential parent node is not full, process 800 may proceed directly to block 812. At block 812, process 800 involves establishing a bidirectional data link between the potential parent node and the low power device 110. Further, the potential parent node may respond to the neighbor solicitation message from the low power device 110 with the neighborhood advertisement message at the time scheduled from the neighbor solicitation message received in block 802. The Neighbor Advertisement message may include a target address option 300 indicating the target MAC address and IPv6 address of the potential parent node. In addition, the Neighbor Advertisement message may provide a node status option 400 with a node status indicating that the bidirectional data link is successful.

FIG. 9 is an example of a process of removing links between nodes when the neighbor cache of the potential parent node is full. At block 902, process 900 includes determining if the potential parent node's neighborhood cache is full. If the neighbor cache is not full, process 900 may repeat the determination in block 902 until the neighbor cache is full. In one example, block 902 may be initialized when a potential parent node receives an adjacency solicitation message from an adjacency device with a higher priority (eg, a low power device).

If the neighbor cache is full and the potential parent node receives a neighbor solicitation message from a neighbor device with a higher priority, in block 904, process 900 will remove the potential parent node from the neighbor cache. Includes identifying one or more mains power neighbors, or any other neighbor based on other criteria. For example, a potential parent node may identify a mains neighbor with a poor neighbor non-arrival detection (NUD) success rate as a mains neighbor available for removal. In addition, the potential parent node is the main power neighbor that has the longest time since the potential parent node received a Neiva Discovery Protocol (NDP) message from the main power neighbor, or any other criterion. Other neighbors can be identified.

At block 906, process 900 includes sending a non-solicitation neighbor advertising message to the identified mains neighbor indicating that the mains neighbor will be removed from the bidirectional data link with the potential parent node. .. The node advertising message may include a node status option 400 with a node status display indicating that the neighbor cache entry for the identified neighbor has been deleted or will be deleted. Upon receiving such a node advertising message, the identified mains neighbor can obtain a new bidirectional data link with an alternative potential parent node. In addition, a potential parent node that has freed up cache space can create a bidirectional data link with a high priority neighbor device.

General considerations

A number of specific details are provided herein to provide a complete understanding of the invention of the present application. However, those skilled in the art will appreciate that the invention of the present application can be practiced without these specific details. In other examples, methods, devices, or systems that may be known to those of skill in the art are not described in detail so as not to obscure the invention of the present application.

The features described herein are not limited to a particular hardware architecture or configuration. The computing device can include any suitable configuration of components that provide results subject to one or more inputs. Suitable computing devices include stored software (ie, on the memory of a computer system) that programs or configures a computing system from a general purpose computing device to a dedicated computing device that implements one or more aspects of the invention. Includes a multipurpose microprocessor-based computer system that accesses computer-readable instructions stored in. Any suitable programming, script, or other type of language, or combination of languages, to implement the teachings contained herein in the software used to program or configure computing devices. However, it can be used.

Aspects of the methods disclosed herein may be performed in the operation of those computing devices. The order of the blocks presented in the above embodiment can be changed, for example, the blocks can be reordered, combined, and / or divided into subblocks. Certain blocks or processes can be executed in parallel.

The use of "adapted to" or "configured to" herein does not preclude devices adapted or configured to perform additional tasks or steps, open. It is intended as a comprehensive language. In addition, the use of "based on" is the addition of one or more described conditions or values "based on" processes, steps, calculations, or other actions that actually exceed those described. It is intended to be open and inclusive in that it may be based on conditions or values. The headings, lists, and numbering contained herein are for convenience of explanation only and are not meant to be limiting.

The invention of the present application has been described in detail with respect to specific embodiments thereof, but it will be understood that those skilled in the art can easily make modifications, modifications, and equivalents to those embodiments with the above understanding. .. Accordingly, this disclosure is presented for purposes of illustration, not limitation, and does not preclude inclusion of modifications, modifications, and / or additions to the invention that are readily apparent to those of skill in the art. Please understand.

Claims (20)

In the method of finding a neighboring node,
In the first node, a step of receiving a neighborhood solicitation message, wherein the neighborhood solicitation message is
A first indication that the second node is a low power device, and
A step to receive, including a first scheduled response time,
In the step of transmitting the first neighborhood advertisement message by the first node at the first scheduled response time, the first neighborhood advertisement message is a step.
A second display indicating that the neighborhood cache of the first node is not available, and
A step to send, including a second scheduled response time,
The step of removing one or more nodes from the neighborhood cache,
A step of receiving a second neighbor solicitation message from the second node by the first node at the second scheduled response time, as well as.
A method comprising linking the first node with the second node. The step of removing the one or more nodes from the neighborhood cache is
A step of identifying the one or more nodes linked to the first node, and.
A second Neighbor Advertising message with a node status display that the Neighbor Cache entry for one or more nodes has been deleted or deleted is sent to the one or more nodes by the first node. The method of claim 1, comprising a step of transmitting. The one or more nodes removed from the Neighbor Cache are the mains power node, the node with poor Neiva Non-Achievement Detection (NUD) success rate, and the first node has not received the Neighbor Discovery Protocol message within the time threshold. Nodes or combinations thereof,
The method according to claim 2. The first aspect of the present invention comprises the step of increasing the priority level of the second node higher than that of at least one main power node upon receiving the first indication that the second node is a low power device. the method of. The first neighborhood advertising message is
i) Identifying the set of link-layer addresses associated with the first node and
ii) Includes a target address option, including the identification of a set of IPv6 addresses associated with each link layer address of the first node.
The method according to claim 1. During the step of linking the first node to the second node, the first node sends a non-solicitation neighborhood advertising message containing a new node status indicating a lack of IP layer connectivity. The non-solicitation neighborhood advertising message is sent as soon as the lack of IP layer connectivity is determined, and the non-solicitation neighborhood advertising message is sent at a subsequent scheduled response time. ,include,
The method according to claim 1. Upon displaying the change from the first node to at least one IPv6 address for the link layer address associated with the first node during the step of linking the first node to the second node, said. A step of sending a non-solicitation Neighbor Advertisement message, including displaying at least one modified IPv6 address for a link layer address, wherein the non-solicitation Neighbor Advertisement message is a modification to the at least one IPv6 address. The non-solicitation Neighbor Advertisement message is sent as soon as it is determined, and the non-solicitation Neighbor Advertisement message is sent at a subsequent scheduled response time, including a step to send.
The method according to claim 1. The method according to claim 7, wherein the non-solicitation neighborhood advertising message is transmitted to each node linked to the first node. A node in the network
Processors that are configured to execute computer-readable instructions, and
When executed by the processor, it includes memory configured to store computer-readable instructions that cause the processor to perform an operation.
The operation is
A step of receiving a first neighbor solicitation message containing a first scheduled response time from an additional node, and
A step of sending a first neighborhood advertising message to the additional node during the first scheduled response time, and.
A node, including the step of establishing a link with the additional node. The processor
A step of reserving space in the neighborhood cache for the one or more preferred nodes based on the capabilities of the one or more preferred nodes, wherein the one or more preferred nodes include the additional node. It is configured to perform operations that include a step to reserve,
The node according to claim 9. The first neighborhood advertising message includes a second scheduled response time.
The processor
The second scheduled response time is further configured to include an operation including sending a second Neighbor Advertising message indicating availability in the Neighbor Cache to the additional node.
The node according to claim 9. The operation is
A step of removing one or more nodes from the neighborhood cache is further included prior to the step of sending the second neighborhood advertising message.
The step of removing the one or more nodes from the neighborhood cache is
Steps to identify one or more mains nodes linked to said node, and
The node sends a third Neighbor Advertising message to the one or more mains power nodes with a node status indication that the Neighbor Cache entry for the one or more nodes has been deleted or deleted. Including steps and
The node according to claim 11. Including more resource consumption measurement hardware,
The node is a measurement node of the resource consumption measurement network.
The node according to claim 9. The first neighborhood solicitation message includes an indication that the additional node contains an elevated priority level based on the additional node receiving power from the battery.
The indication that the additional node contains an elevated priority level initiates the removal of one or more mains power nodes from the neighbor cache when the neighbor cache is full.
The node according to claim 9. The link with the additional node includes an interim link containing an entry to the interim cache position of the additional node.
The node according to claim 9. It ’s a node,
Processors that are configured to execute computer-readable instructions, and
A memory that, when executed by the processor, is configured to store computer-readable instructions that cause the processor to perform an operation.
Including
The operation is
Steps to establish a link with a potential parent node,
A step of receiving a non-solicitation neighbor advertisement message from the potential parent node, indicating a status change of the potential parent node, and.
A node that includes a step of updating the neighbor cache stored in the memory to deal with the status change of the potential parent node. The status change to the potential parent node includes an indication that there is no IP layer connectivity at the potential parent node.
The node according to claim 16. The step of updating the neighbor cache to deal with the status change of the potential parent node is
Including the step of establishing a new link with a different neighbor node and updating the neighbor cache with information about the different neighbor node.
The node selects the different neighbor node based on the device capability option and the node status option of the different neighbor device.
The node according to claim 17. The non-solicitation neighborhood advertising message contains a target address option format and contains.
The status change for the potential parent node indicated in the target address option format comprises changing the IPv6 address of at least one of the potential parent nodes.
The node according to claim 16. The step of updating the neighbor cache to address the status change of the potential parent node is
The step comprising changing the at least one IPv6 address of the potential parent node in the neighborhood cache.
The node according to claim 19.

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